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3 years ago

If you where asked to convert 4.2*10^22 atoms of aluminum to moles, which of the following should you use for the conversion

Chemistry

1 answer:

g100num [7]3 years ago

7 0

Answer:

0.0697 moles

Explanation:

We are being asked 4.2 x 10^22 atoms of aluminium to moles the following should be used for conversion.

Fraction of 1 mole Al over six point zero two two times ten to twenty third power atom Al.

that is 1 mole = 6.022 x10^23 atom

? = 4.2 x 10^22 atom

by cross multiplication

(1 mole x 4.2 x 10^22)/ 6.022 x 10^23 = 0.0697 moles

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Which occurs whenever valence electrons are shared or transferred between atoms?

Tanzania [10]

Whenever electrons are shared or transferred between atoms there is a chemical reaction.

The electrons that are being transferred between atoms (two or more) create new bonds, which enable the production of a new substance. This process is then known as a chemical reaction.

4 0

3 years ago

Question List (4 items) (Drag and drop into the appropriate area) Find the volume of HCl that will neutralize the base. Find the

expeople1 [14]

The question is incomplete, the complete question is:

The solubility of slaked lime, $Ca(OH)_2$ , in water is 0.185 g/100 ml. You will need to calculate the volume of $2.50\times 10^{-3}$ M HCl needed to neutralize 14.5 mL of a saturated

Answer: The volume of HCl required is 290mL, the mass of $Ca(OH)_2$ is 0.0268g, the moles of

Explanation:

Given values:

Solubility of $Ca(OH)_2$ = 0.185 g/100 mL

Volume of $Ca(OH)_2$ = 14.5 mL

Using unitary method:

In 100 mL, the mass of $Ca(OH)_2$ present is 0.185 g

So, in 14.5mL. the mass of $Ca(OH)_2$ present will be = $\frac{0.185}{100}\times 14.5=0.0268g$

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

Given mass of $Ca(OH)_2$ = 0.0268 g

Molar mass of $Ca(OH)_2$ = 74 g/mol

Plugging values in equation 1:

$\text{Moles of }Ca(OH)_2=\frac{0.0268g}{74g/mol}=0.000362 mol$

Moles of $OH^-$ present = $(2\times 0.000362)=0.000724mol$

The chemical equation for the neutralization of calcium hydroxide and HCl follows:

$Ca(OH)_2+2HCl\rightarrow CaCl_2+2H_2O$

By the stoichiometry of the reaction:

Moles of $OH^-$ = Moles of $H^+$ = 0.000724 mol

The formula used to calculate molarity:

$\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}$ .....(2)

Moles of HCl = 0.000724 mol

Molarity of HCl = $2.50\times 10^{-3}$

Putting values in equation 2, we get:

$2.50\times 10^{-3}mol=\frac{0.000724\times 1000}{\text{Volume of solution}}\\\\\text{Volume of solution}=\frac{0.000725\times 1000}{2.50\times 10^{-3}}=290mL$

Hence, the volume of HCl required is 290mL, the mass of $Ca(OH)_2$ is 0.0268g, the moles of

5 0

3 years ago

A ring costs $36 more than a bracelet. the cost of the bracelet is 4/7 the cost of the ring. find the total of the two items.

avanturin [10]

So let's use some equations to represent the data [let R= cost of ring & B= cost of bracelet]

R= B + $ 36 .... (1)

B= $\frac{4}{7}$ × R ... (2)

By using simultaneous equations to solve for B and R.
Substitute eq. (1) into eq. (2)

B = $\frac{4}{7}$ × (B + $36)

B = $\frac{4}{7}$ B + $\frac{144}{7}$

$( \frac{7}{7} - \frac{4}{7} ) B = \frac{144}{7}$

$\frac{3}{7} B = \frac{144}{7}$

⇒ B = $48

By substituting value of B into ea (1)

If R = B + $36

R = ($48) + $36

= $84

∴ the total of the two items = R + B
= $84 + $48
 = $132

7 0

3 years ago

PLEASE HELP!!!!!!!

Anna11 [10]

Answer:

i think 30

Explanation:

5 0

2 years ago

Describe the three steps of solution formation. be sure to include the details regarding the dissolving of the substance

Elza [17]

The three steps involve;

Step 1: Separation/expansion of the solute particles

Step 2: Separation/expansion of the solvent particles

Step 3; Combining the solute and solvent particles

The first two steps are usually endothermic. Step 3, nonetheless, can be either exothermic or endothermic and is significant in determining whether the dissolving process will be endothermic or exothermic.

8 0

2 years ago

Read 2 more answers